Ultra-long Cycling Performance Research Articles

Enhanced energy density and wide potential window for K incorporated MnO2@carbon cloth supercapacitor

Based on the redox couple reaction of Mn3+/Mn4+, the theoretical capacitance of manganese dioxide (MnO2) has a very high value of 1370 F/g but the specific capacitance of MnO2 in the reported literature is still under 300 F/g. The potential window of MnO2 in the previously published studies is approximately 1 V which, considering E = 1/2CV2, limits the power and energy densities far below the theoretical value. In this work, we developed an ultra-thin K+ doped δ-MnO2 nanosheets array electrode the potential window of which extended to 0–1.2 V with a highly reversible capacitance of 366 F/g. When the potential window reaches 1.2 V, the fast-redox reaction of MnO2 and the K+ intercalation/deintercalation process restrains water decomposition in kinetics. A high potency aqueous asymmetric supercapacitor (K-MnO2//AC) was drafted with K-MnO2 as a positive electrode which exhibited a stable working potential window of 0–2.2 V in 1 M Na2SO4 aqueous electrolyte. This device has demonstrated an excellent energy density of 56 Wh/kg at a power density of 550 W/kg and an ultralong cycle performance with capacitance retention of 98% over 10,000 cycles at the current density of 10 A/g. This approach leads to new prospects for emerging high workable potential window aqueous energy storage devices.

Confining Sb nanoparticles in bamboo-like hierarchical porous aligned carbon nanotubes for use as an anode for sodium ion batteries with ultralong cycling performance

Sb nanoparticles are confined in bamboo-like hierarchical porous aligned carbon nanotubes for use as an anode for sodium ion batteries with ultralong cycling performance.

A microscopic spatially confined strategy to realize completely reversible self-healing lattice restoration of MoS2 for ultrastable reversible sodium-ion storage

Double-layer carbon-encapsulated MoS2 (C@MoS2@C) nanocubes were synthesized and used as an anode for ultralong cycling performance sodium-ion batteries, based on a microscopic spatially confined strategy.

Design and synthesize hollow spindle Ni-doped Co9S8@ZnS composites and their enhanced cycle performance

Transition metal sulfides are considered as a kind of promising anode for lithium ion batteries due to their high theoretical capacity, but their further development are still greatly hampered by their volume expansion and electrical conductivity problems. Here, hollow spindle Ni-doped Co9S8@ZnS composites are synthesized by a simple two-steps hydrothermal method. The unique hollow structure, multi-component synergistic effect as well as effective ion doping can improve the comprehensive performance. When the as-obtained composites are used for the lithium ion batteries, which exhibit an ultra-long cycle performance. The capacity of 585 mAh/g can be maintained at 0.1 A/g after a long cycling of 1000 cycles. Even when the current density is raised to 1 A/g, the composites exhibit a high reversible discharge capacity of 758 mAh/g after 500 cycles.

Tuning Interface Bridging Between MoSe2 and Three-Dimensional Carbon Framework by Incorporation of MoC Intermediate to Boost Lithium Storage Capability

HighlightsMoSe2/MoC/C multiphase boundaries boost ionic transfer kinetics.MoSe2 (5–10 nm) with rich edge sites is uniformly coated in N-doped framework.The obtained MoSe2 nanodots achieved ultralong cycle performance in LIBs and high capacity retention in full cell.Interface engineering has been widely explored to improve the electrochemical performances of composite electrodes, which governs the interface charge transfer, electron transportation, and structural stability. Herein, MoC is incorporated into MoSe2/C composite as an intermediate phase to alter the bridging between MoSe2- and nitrogen-doped three-dimensional (3D) carbon framework as MoSe2/MoC/N–C connection, which greatly improve the structural stability, electronic conductivity, and interfacial charge transfer. Moreover, the incorporation of MoC into the composites inhibits the overgrowth of MoSe2 nanosheets on the 3D carbon framework, producing much smaller MoSe2 nanodots. The obtained MoSe2 nanodots with fewer layers, rich edge sites, and heteroatom doping ensure the good kinetics to promote pseudo-capacitance contributions. Employing as anode material for lithium-ion batteries, it shows ultralong cycle life (with 90% capacity retention after 5000 cycles at 2 A g−1) and excellent rate capability. Moreover, the constructed LiFePO4//MoSe2/MoC/N–C full cell exhibits over 86% capacity retention at 2 A g−1 after 300 cycles. The results demonstrate the effectiveness of the interface engineering by incorporation of MoC as interface bridging intermediate to boost the lithium storage capability, which can be extended as a potential general strategy for the interface engineering of composite materials.

Na2Li2Ti6O14 nanowires as ultra-long cycling performance anode material for lithium ion storage

Na2Li2Ti6O14 nanowires prepared through electrospinning and subsequent calcination method are reported as an anode material for lithium ion storage. During the initial cycle, as-synthesized Na2Li2Ti6O14 nanowires deliver a quite flat charge platform at 1.32 V with the charge capacity of 94.0 mAh g-1 at 100 mA g-1. Specifically, after a long cycle of 2500 times, Na2Li2Ti6O14 nanowires still hold a reversible charge capacity of 88.8 mAh g-1 with a remarkable capacity retention of 94.47%, which also show a high Coulombic efficiency of 99.83%. The favorable electrochemical performance may stem from its unique nanostructures, which not only preserve structural integrity during repeated cycles but also reduce the distance of lithium ion transport.

Red phosphorus confined in hierarchical hollow surface-modified Co9S8 for enhanced sodium storage

The encapsulation-type structured P@Co9S8 materials assembled with surface-modified hierarchical hollow spherical Co9S8 exhibit ultralong cycling and high rate performance for SIBs.

N/P-Dual-Doped Carbon-Coated Na3V2(PO4)2O2F Microspheres as a High-Performance Cathode Material for Sodium-Ion Batteries.

Na3V2(PO4)2O2F (NVPOF) is attracting great interest due to its large capacity and high working voltage. However, poor electronic conductivity limits the electrochemical performance of NVPOF. Herein, we fabricate N/P-dual-doped carbon-coated NVPOF microspheres (labeled as NVPOF@P/N/C) via a hydrothermal process followed by heat treatment. This microsphere-structured NVPOF@P/N/C composite has a relatively high tap density of 1.22 g/cm3. TEM and XPS results reveal that the dual-doped carbon layer is tightly coated on the NVPOF surface due to the bridging effect of P and has a good protective effect on NVPOF. Density functional theory (DFT) calculations confirm that a N/P-dual-doped carbon layer is advantageous to achieve higher electronic conductivity and lower migration activation energy than those of the undoped and single N- or P-doped carbon layer. As a cathode material for a sodium-ion battery (SIB), NVPOF@P/N/C exhibits high capacity (128 mAh/g at 0.5 C and 122 mAh/g at 2 C) and ultralong cycle performance (only 0.037% capacity fading rate per cycle in 500 cycles at 2 C). We believe that the NVPOF@P/N/C composite is appealing for high-performance SIBs with large energy density.

Hierarchical porous activated carbon derived from Enteromorpha prolifera for superior electrochemical capacitive behavior

A low-cost porous carbon material is introduced by using marine bloom green alga—Enteromorpha prolifera—as raw material towards simple freeze-drying pretreatment and subsequent ZnCl2 activation procedure. This strategy is aimed at producing activated carbons with high surface area (1910.84 m2 g−1) and combining macro-/meso-/micropores with high total pore volume (up to 2.86 cm3 g−1), at a ZnCl2/E. prolifera impregnation ratio of 4 at 600 °C. The application of the activated carbons operating in electric double-layer capacitors (EDLCs) shows high specific capacitance of 332.4 F g−1 at a rate of 0.2 A g−1 in 1 M H2SO4, much better than those in 6 M KOH (167 F g−1). Moreover, the assembled symmetric devices yielded ultra-long cycling performance (100% after 5500 cycles at 0.5 A g−1). Benefiting from the cheap biomass precursor, we believe that this simple precursor synthesis route offers excellent potential for facile large-scale material production which may serve as a potential candidate for energy storage.

Fast and stable potassium-ion storage achieved by in situ molecular self-assembling N/O dual-doped carbon network

Nitrogen and oxygen dual-doped amorphous carbon network (NOCN) facilely prepared via self-assembly method in this study as potassium ion battery’ anode for ultra-long and superior-rate capability. The as-synthesized NOCN exhibits an excellent reversible capacity of 464.9 mAh g-1 at 0.05 A g-1, outstanding performance of 175 mAh g-1 at a high current density of 5.0 A g-1, and ultra-long cycling performance with capacity decay less than 0.008% per cycle. The superior performance can be attributed to the unique ultra-stable network structure together with N and O co-doped. Supported by detailed fundamental analysis, the higher K-ion storage process in NOCN is contributed by the pseudocapacitive mechanism. The simple synthesis route as well as the hopeful electrochemical property shed a new insight into the quest for carbon-based K-storage anode materials with high energy and long-cycling life.

Stable cross-linked gel terpolymer electrolyte containing methyl phosphonate for sodium ion batteries

The novel bifunctional methyl phosphonate which combines the good polymerization ability of acrylate, the adjustable flexibility of ethylenedioxy group and the flame retardant properties of phosphonate is designed and synthesized. The corresponding ternary gel polymer electrolyte is prepared by radical cross-linking copolymerization. The gel terpolymer electrolyte has good thermal stability with the onset decomposition temperature of 250 °C, excellent electrochemical stability of up to 5.0 V (vs. Na+/Na) and high ionic conductivity of 5.13 mS cm−1. Moreover, the gel polymer electrolyte can enhance interfacial adhesion between the membrane and the electrodes. The Na3V2(PO4)3/Na cell using phosphorus containing gel terpolymer electrolyte shows ultra-long cycling performance and better cycle stability and rate performance than the corresponding conventional liquid electrolyte, phosphorus containing gel bipolymer electrolyte and other crosslinker based cells. Meanwhile, the glass fiber separator filled with gel polymer electrolyte maintains better integrity than liquid electrolyte after 1000 cycles, which means the gel polymer electrolyte has good mechanical property and compatibility. The gel polymer electrolyte based sodium-ion battery also exhibits superior cycle stability compared to the battery with liquid electrolyte when running at high temperature of 60 °C. The strong interaction between methyl phosphonate and sodium ion is studied by FT-IR, 31P NMR and HRMS, and demonstrated by theoretical calculation.

Construction of Mn-Zn binary carbonate microspheres on interconnected rGO networks: creating an atomic-scale bimetallic synergy for enhancing lithium storage properties.

Transition metal carbonates (TMCs), as promising anode materials for high-performance lithium ion batteries, possess the advantages of abundant natural resources and high electrochemical activity; however, they suffer from poor Li+/e- conductivities and serious volume changes during the charge/discharge process. Constructing multicomponent carbonates by introducing binary metal atoms, as well as designing a robust structure at the micro and nanoscales, could efficiently address the above problems. Therefore, single-phase MnxZn1-xCO3 microspheres anchored on 3D conductive networks of reduced graphene oxide (rGO) are facilely synthesized via a one-pot hydrothermal method without any structure-directing agents or surfactants. Due to the well-designed architecture and atomic-scale bimetallic synergy, the MnxZn1-xCO3/rGO composites show superior lithium storage capacity, good rate capability and ultra-long cycling performance. Specifically, the Mn2/3Zn1/3CO3/rGO composites could deliver a high capacity of 1073 mA h g-1 at 200 mA g-1. After 1700 cycles at a high rate of 2000 mA g-1, a stable capacity of 550 mA h g-1 can be maintained with the capacity retention approaching 88.6%. Density functional theory (DFT) calculations indicate that the partial Zn substitution in MnCO3 could significantly decrease the band gap of the crystal, resulting in great improvement of electric conductivity. Moreover, the commercial potential of the MnxZn1-xCO3/rGO composites is investigated by assembling full cells, suggesting good practical adaptability of the composite anodes. This work would provide a feasible and cost-efficient method to develop high-performance anodes and stimulate many more related research studies on TMC-based electrodes.

Tunable energy storage capacity of two-dimensional Ti3C2Tx modified by a facile two-step pillaring strategy for high performance supercapacitor electrodes.

This paper proposed to tailor the layer microstructures of two-dimensional Ti3C2Txvia a facile Li+ pre-pillaring and successive pillaring strategy by various cations. By ion exchange with pre-intercalated Li+, as well as "coulombic attraction" to electronegative Ti3C2Tx, various inexpensive and column-like K+, Ca2+, Mg2+, Al3+ and NH4+ cations were migrated into the Ti3C2Tx interlayers. By expanding the interlayer about 17.02%, as well as enhancing the electron density of Ti atoms and C atoms, the Al3+ intercalated MXene Ti3C2Tx sheets delivered the highest specific capacity of 175 F g-1 at 0.3 A g-1. Coupling the Ti3C2Tx-Al3+ working electrode with a platinum counter electrode and a Hg/HgO reference electrode, the single electrode (calculated from a three-electrode system) exhibited a high energy density of 87.5 W h kg-1 and a high power density (2100 W kg-1) with an ultra-long and stable cycling performance. The binding energies of the intercalated ions with hydroxyl groups, the Bader charge distribution and degree of electron localization were evaluated by density functional theory calculations to further validate the ultra-high energy storage capacity of Al3+ pillared-Ti3C2Tx in the present study.

MoP hollow nanospheres encapsulated in 3D reduced graphene oxide networks as high rate and ultralong cycle performance anodes for sodium-ion batteries.

Molybdenum phosphide (MoP), regarded as a promising anode material for sodium-ion batteries due to its superior conductivity and high theoretical specific capacity, still suffers from rapid capacity decay because of a large volume change and weak diffusion kinetics. Hollow nano-structures will be an effective solution to alleviate structural strain and improve cycling stability. Yet the preparation of MoP needs a high temperature phosphorization procedure which would cause agglomeration and structure collapse, making it difficult to achieve hollow nano-structures. Herein, caged by 3D graphene networks, MoP hollow nanospheres encapsulated in 3D reduced graphene oxide networks (H-MoP@rGO) were prepared successfully, and benefiting from the merits of the hollow nano-structure and flexibility of rGO, H-MoP@rGO demonstrates a superior cycle performance of 353.8 mA h g-1 at 1 A g-1 after 600 cycles and an extraordinary rate performance of 183.4 mA h g-1 at an ultrahigh current density of 10 A g-1 even after 3000 cycles.

A Nonpresodiate Sodium-Ion Capacitor with High Performance.

Sodium-ion capacitors (SICs) have received intensive attention due to their high energy density, high power density, long cycle life, and low cost of sodium. However, the lack of high-performance anode materials and the tedious presodiation process hinders the practical applications of SICs. A simple and effective strategy is reported to fabricate a high-performance SIC using Fe1- x S as the anode material and an ether-based electrolyte. The Fe1- x S electrode is found to undergo a reversible intercalation reaction after the first cycle, resulting in fast kinetics and excellent reversibility. The Fe1- x S electrode delivers a high capacity of 340 mAh g-1 at 0.05 A g-1 , 179 mAh g-1 at high current of 5 A g-1 and an ultralong cycling performance with 95% capacity retention after 7000 cycles. Coupled with a carbon-based cathode, a high-performance SIC without the presodiation process is successfully fabricated. The hybrid device demonstrates an excellent energy density of 88 Wh kg-1 and superior power density of 11 500 W kg-1 , as well as an ultralong lifetime of 9000 cycles with over 93% capacity retention. An innovative and efficient way to fabricate SICs with both high energy and power density utilizing ether-based electrolytes can be realized to eliminate the presodiation process.

Ultrastable Potassium Storage Performance Realized by Highly Effective Solid Electrolyte Interphase Layer.

Potassium ion-batteries (PIBs) have attracted tremendous attention recently due to the abundance of potassium resources and the low standard electrode potential of potassium. Particularly, the solid-electrolyte interphase (SEI) in the anode of PIBs plays a vital role in battery security and battery cycling performance due to the highly reactive potassium. However, the SEI in the anode for PIBs with traditional electrolytes is mainly composed of organic compositions, which are highly reactive with air and water, resulting in inferior cycle performance and safety hazards. Herein, a highly stable and effective inorganic SEI layer in the anode is formed with optimized electrolyte. As expected, the PIBs exhibit an ultralong cycle performance over 14 000 cycles at 2000 mA g-1 and an ultrahigh average coulombic efficiency over 99.9%.

NH4+ Topotactic Insertion in Berlin Green: An Exceptionally Long-Cycling Cathode in Aqueous Ammonium-Ion Batteries

Aqueous batteries represent promising solutions for large-scale energy storage considering the cost, safety, and performance. Despite the tremendous efforts devoted to the metal cations as charge carriers for batteries, scarce attention has been paid to the non-metal cations such as proton or ammonium. In this study, we report that a Berlin green framework exhibits much greater structural compatibility for NH4+ (de)insertion than Na+ and K+. Ex situ structural studies reveal that the topochemistry of NH4+ in Berlin green is of nearly zero strain. The NH4+ topotactic performance gives rise to a higher operation potential and an ultralong cycling performance of 50,000 cycles with 78% capacity retention, far superior to Na+ and K+ (de)insertion. Furthermore, we propose a double-ion battery, where the Berlin green cathode hosts NH4+ and sodium titanium phosphate NaTi2(PO4)3 accommodates Na+ during operation. Such a new system exhibits promising results in capacity and cycling life. Our results point to a new ...

A Dealloying Synthetic Strategy for Nanoporous Bismuth-Antimony Anodes for Sodium Ion Batteries.

Metal-based anodes have recently aroused much attention in sodium ion batteries (SIBs) owing to their high theoretical capacities and low sodiation potentials. However, their progresses are prevented by the inferior cycling performance caused by severe volumetric change and pulverization during the (de)sodiation process. To address this issue, herein an alloying strategy was proposed and nanoporous bismuth (Bi)-antimony (Sb) alloys were fabricated by dealloying of ternary Mg-based precursors. As an anode for SIBs, the nanoporous Bi2Sb6 alloy exhibits an ultralong cycling performance (10 000 cycles) at 1 A/g corresponding to a capacity decay of merely 0.0072% per cycle, due to the porous structure, alloying effect and proper Bi/Sb atomic ratio. More importantly, a (de)sodiation mechanism ((Bi,Sb) ↔ Na(Bi,Sb) ↔ Na3(Bi,Sb)) is identified for the discharge/charge processes of Bi-Sb alloys by using operando X-ray diffraction and density functional theory calculations.

Few‐Layer MoSe2 Nanosheets with Expanded (002) Planes Confined in Hollow Carbon Nanospheres for Ultrahigh‐Performance Na‐Ion Batteries

AbstractSodium‐ion batteries (SIBs) are considered as a promising alternative to lithium‐ion batteries, due to the abundant reserves and low price of Na sources. To date, the development of anode materials for SIBs is still confronted with many serious problems. In this work, encapsulation‐type structured MoSe2@hollow carbon nanosphere (HCNS) materials assembled with expanded (002) planes few‐layer MoSe2 nanosheets confined in HCNS are successfully synthesized through a facile strategy. Notably, the interlayer spacing of the (002) planes is expanded to 1.02 nm, which is larger than the intrinsic value of pristine MoSe2 (0.64 nm). Furthermore, the few‐layer nanosheets are space‐confined in the inner cavity of the HCNS, forming hybrid MoSe2@HCNS structures. When evaluated as anode materials for SIBs, it shows excellent rate capabilities, ultralong cycling life with exceptional Coulombic efficiency even at high current density, maintaining 501 and 471 mA h g−1 over 1000 cycles at 1 and 3 A g−1, respectively. Even when cycled at current densities as high as 10 A g−1, a capacity retention of 382 mA h g−1 can be achieved. The expanded (002) planes, 2D few‐layer nanosheets, and unique carbon shell structure are responsible for the ultralong cycling and high rate performance.

Controllable Electrochemical Synthesis of Copper Sulfides as Sodium-Ion Battery Anodes with Superior Rate Capability and Ultralong Cycle Life.

Sodium-ion batteries (SIBs) are prospective alternative to lithium-ion batteries for large-scale energy-storage applications, owing to the abundant resources of sodium. Metal sulfides are deemed to be promising anode materials for SIBs due to their low-cost and eco-friendliness. Herein, for the first time, series of copper sulfides (Cu2S, Cu7S4, and Cu7KS4) are controllably synthesized via a facile electrochemical route in KCl-NaCl-Na2S molten salts. The as-prepared Cu2S with micron-sized flakes structure is first investigated as anode of SIBs, which delivers a capacity of 430 mAh g-1 with a high initial Coulombic efficiency of 84.9% at a current density of 100 mA g-1. Moreover, the Cu2S anode demonstrates superior capability (337 mAh g-1 at 20 A g-1, corresponding to 50 C) and ultralong cycle performance (88.2% of capacity retention after 5000 cycles at 5 A g-1, corresponding to 0.0024% of fade rate per cycle). Meanwhile, the pseudocapacitance contribution and robust porous structure in situ formed during cycling endow the Cu2S anodes with outstanding rate capability and enhanced cyclic performance, which are revealed by kinetics analysis and ex situ characterization.